Witnesses heard a ‘bang’ after he was picked up and thrown overboard during horseplay and it is believed he may have hit his head on his way into the water.

Despite the attempts of the stag, Youssef Ismail, and friend Andre Van Eck, who threw him, Nish never resurfaced and his body was only recovered four days later.

The 31-year-old, who worked as risk manager in London, had been drinking his first beer of the day with 12 friends while the boat was anchored for lunch on the River Tagus.

Westminster Coroner’s Court was told all of the party has planned on jumping in after their friend had been thrown overboard to swim to shore.

Giving evidence, Mr Van Eck told the court he had planned to throw Nish in the water at that specific spot after consulting with the captain, who assured him it was ‘safe’.

The best man had been on a stag do in Portugal with his friends (Picture: SWNS)

Recalling what happened he said: ‘We were on the boat standing, and Nish was just opposite me.

‘Just before that, he went to get his phone, and Youssef took the phone off him. He said, “look, I will take the photos”.’

He said they were chatting for a bit, before he ‘told the guys to move out of the way’, at which point he picked him up and threw him in.

He added: ‘And to my recollection, he grabbed one of the rails, and half swung back on himself, hitting the side of the boat – whether it was his head or his body, I don’t know, but there was a big bang. He went under.

The group was enjoying their first beer of the day on the River Tagus (Picture:Getty)

‘I was just about to jump. I saw Youssef had jumped already. And that was the last time I saw Nish.

‘I swam underneath the boat, but we couldn’t find him. My assumption was he would just come to the surface at some point.’

He explained the ‘intention was never there to hurt him’

Asked if Nish was ‘willing’ to be thrown in, he said he was more concerned about his beer.

Mr Van Eck said: ‘He protested in the sense he had a beer in his hand. We had just started drinking. On a stag do beer is precious.’